1. Field of the Invention
The present invention relates to electric powered models, for example, model trains and particularly to a low-cost sound system for model trains which comprises an electronic sound chip for storing digitized sounds with the sound chip containing a sound processor for producing sound from at least one of the voice channels in the sound chip, and a microprocessor for control; wherein the system uses a free comparator present in the microprocessor that controls sound card operation by detecting positive and negative DC offsets by voltage to frequency conversion and, thereby activating one of two “voices” or channels of sound, said offset detection system self-calibrates on the initial power on, and the calibration values are measured and stored internally in non-volatile storage for later comparison against the DC offset to frequency thresholds. The system detects loss of power, which mutes the audio during power interruptions for seamless model train direction control.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Model train systems have been in existence for decades and during that time technology has advanced to allow hobbyists to enjoy more realistic model trains. Model train sound simulation systems have greatly benefited from technological advances. The earliest model train systems did not have sound simulation capabilities. Later, miniature whistles, horn, chuffing sounds, bells, and the like were added to imitate sounds that might be generated by a full-sized train. Digitized sound cards have become popular recently. Unfortunately, many digital model train sound systems have become increasingly expensive for the hobbyist.
The conventional prior art mode of operation is controlled by DC offsets on the AC track power. To trigger a horn, a positive DC offset is applied to the track. To trigger the Bell a negative DC offset is applied to the track. All other sounds are automatically triggered, as appropriate, except an external switch on the wheels controls the chuff cadence on the steamer version.
In conventional prior art operation, the power supply can “kick-back” a voltage pulse into the track as it loses regulation. This is common to the switching power supplies located on sound cards. This “kick-back” can trigger undesirable responses in the electronics in the locomotives the sound commander is located in and cause a failure of the locomotive to sequence direction properly because the locomotive direction control is managed by track power interruption. Before electronics entered into the direction control mechanisms, a solenoid advanced a pawl to reverse the motor connections and thus reversed the motor direction. As the locomotives advanced, the prior art devices now utilize electronics to perform this function. The electronics respond much faster than the mechanical reversing systems in these newer locomotives. This fast response time interprets the “kick-back” as 2 power interruptions; thus the prior art locomotive does not reverse direction correctly. To mitigate this, prior art technology uses a battery to supply power to the sound electronics at this critical time.
Several prior art methods have been used for detection of the positive and negative DC offset on the track. The simplest is an “integrator” or low pass filter. This filter converts the pulsing offset into a DC voltage to turn on a pair of transistors acting as switches for positive and negative offsets. These switches are used to activate the appropriate sound. This design is in the public domain and used by many sound cards in the market.
Lionel has a system in which a 324 op-amplifier is configured to oscillate at a nominal frequency. This frequency is driven higher or lower by the application of the DC offset to the amplifier, produced by the typical “integrator” described above. A sound processor that produces the sounds detects this frequency change to select the appropriate sound (horn or bell).
Prior art sound triggering in conventional mode uses simple Positive or Negative DC generation and detection. It is clear that this permits only 2 distinct sounds to be triggered. These are classified as horn and bell; or generically Sound #1 or Sound #2. QSI, a leader in sound system design, has utilized a “state-full” method of activating more than these 2 basic sounds. Their system is based on a sequence of “fast” pulses to select the sound.
For example: it takes about 0.4 second to fully develop an offset on the track to trigger a horn. This offset is about 3v to 5v DC. As the integrator charges, the voltage rises from 0v to the 3v to 5v range. If you apply this offset quickly, the voltage may only reach 2v before it subsides. The QSI system detects these lower voltages, which are not enough to trigger the Horn, and stores the detection of this signal. A series of pulses can pre-select a sound to be activated when the long pulse that creates the 3v to 5v offset. The products that do not detect these fast pulses ignore them as noise.
The prior art systems are overly complex and expensive.
U.S. Patent Application #20050152555, published Jul. 14, 2005 by Pierson, shows a sound system for a model vehicle and/or accessory which includes a control block configured to access predetermined digital data corresponding to a plurality of sound features. The control block is further configured to be responsive to at least one input signal indicative of at least a selected one sound feature to access the predetermined digital data and to generate a sound signal corresponding to the selected sound feature. The sound system further includes a current amplifier responsive to the sound signal configured to drive a speaker to produce the selected sound feature.
Two U.S. Patent Applications #20050023416 published Feb. 3, 2005 and #20040079841 published Apr. 29, 2004 both by Wolf et al., claim a model train operating, sound and control system that provides a user with increased operating realism. Remote control communication capability is provided between the user and the model trains. This feature is accomplished by using a handheld remote control on which various commands may be entered, and a Track Interface Unit that retrieves and processes the commands. The Track Interface Unit converts the commands to modulated signals in the form of data bit sequences (preferably spread spectrum signals) which are sent down the track rails. The model train picks up the modulated signals, retrieves the entered command, and executes it through use of a processor and associated control and driver circuitry. A speed control circuit located inside the model train that is capable of continuously monitoring the operating speed of the train and making adjustments to a motor drive circuit, as well as a novel smoke unit. Circuitry for connecting the Track Interface Unit to an external source, such as a computer, CD player, or other sound source, and have real-time sounds stream down the model train tracks for playing through the speakers located in the model train.
Two U.S. Pat. No. 6,624,537 issued Sep. 23, 2003 and U.S. Pat. No. 6,281,606 issued Aug. 28, 2001 both to Westlake, are for a plural output control station for operating electrical apparatus, such as model electric train engines and accessories. The control station employs a data processor for monitoring and controlling the signals generated at a plurality of transformer-driven power output terminals. An exemplary station includes two variable-voltage alternating current (AC) output channels (TRACK 1 and TRACK 2) and two fixed-voltage AC output channels (AUX 1 & AUX 2). The variable-voltage outputs are controlled by a data processor responsive to respective operator-controlled throttles for varying the AC output voltage and therefore the rate of movement and direction of electric train engines, typically three-rail O-gauge model trains. The variable-voltage outputs can also be offset by the data processor with positive and negative DC voltages for enabling engine functions such as horns, whistles and bells. The variable-voltage outputs are controlled by the data processor to also communicate control parameters to electric train engines for the operation and programming of various electric train engine features and accessories. The plurality of outputs are monitored by the data processor to ensure that predetermined voltage and/or current limits are not exceeded by any individual output and that a predetermined power limit is not exceeded by any individual output or by any combination of outputs.
Four U.S. Pat. No. 6,655,640 issued Dec. 2, 2003, U.S. Pat. No. 6,619,594 issued Sep. 16, 2003, U.S. Pat. No. 6,604,641 issued Aug. 12, 2003 and U.S. Pat. No. 6,457,681 issued Oct. 1, 2002 all to Wolf et al., show a model train operating, sound and control system that provides a user with increased operating realism. Remote control communication capability is provided between the user and the model trains. This feature is accomplished by using a handheld remote control on which various commands may be entered, and a Track Interface Unit that retrieves and processes the commands. The Track Interface Unit converts the commands to modulated signals in the form of data bit sequences (preferably spread spectrum signals) which are sent down the track rails. The model train picks up the modulated signals, retrieves the entered command, and executes it through use of a processor and associated control and driver circuitry. A speed control circuit located inside the model train that is capable of continuously monitoring the operating speed of the train and making adjustments to a motor drive circuit, as well as a novel smoke unit. Circuitry for connecting the Track Interface Unit to an external source, such as a computer, CD player, or other sound source, and have real-time sounds stream down the model train tracks for playing through the speakers located in the model train.
U.S. Pat. No. 6,616,505, issued Sep. 9, 2003 to Reagan, claims a model train sound board interface for making model trains compatible with the LIONEL TRAINMASTER® Command Control system. The model train sound board interface is comprised of circuitry which interprets serial digital data received from the LIONEL TRAINMASTER Command Control transmitter to determine what command the user is sending to the model train engine. Once the command is interpreted the circuitry provides the appropriate output signal to carry out the command. The circuitry of the preferred embodiment includes a microprocessor for interpreting serial data from the LIONEL TRAINMASTER Receiver, negative 5 and approximately negative 9 volt power supplies for providing consistent and filtered power to external sound boards, an H-bridge triac motor driver optically coupled to the microprocessor and DC offset circuitry made up of variable voltage regulators, again optically coupled to the microprocessor. The DC offset circuitry provides positive and negative DC offsets required by many popular aftermarket sound boards for model trains which provide life-like sound effects.
U.S. Pat. No. 5,174,216, issued Dec. 29, 1992 to Miller, describes a digital sound reproducing system for toy trains with stored digitized sounds recalled upon trackside triggering which produces a plurality of sound effects from digital data stored at predetermined addresses in a digital sound memory. A controller connected to the digital sound memory causes recall of a sound data from a predetermined sequence of addresses when triggered. This recalled sound data is converted into an analog audio signal for reproduction by a speaker. In a first embodiment the digital sound reproducing system is disposed in the car of a model train. Magnets disposed between the tracks trigger corresponding sound effects when the digital sound reproducing system detects passage of the magnets. A speed sensor detects the rotation rate of a wheel of the car to permit sound effects to be synchronous with the rate of speed of the model train. The digital sound reproducing system may alternately be disposed in a fixed structure and triggered by a command signal or by detection of passage of the model train. In a second embodiment, a detector indicates when a space may be occupied triggering a randomized sound sequence as background noise.
U.S. Pat. No. 5,555,815, issued Sep. 17, 1996 to Young, discloses a horn control system for model vehicles on a track that includes a sound generation unit mounted on the model vehicle which generates different sounds based on the combination of two inputs, the speed of the vehicle and an operator initiated horn signal. The type of sound is also preferably varied based on how long the horn button is depressed.
U.S. Pat. No. 5,754,094, issued May 19, 1998 to Frushour, indicates a sound generating apparatus for movable objects, particularly model trains, which generates audible sounds from digital signal representations of actual train sounds pre-stored in a memory mounted on the object. In one embodiment, the stored digital sound representations are divided into sets, with each set assigned to a different speed range of movement of the object. Each set includes a plurality of subsets, each containing distinct sound representations which can vary in volume and/or pitch. A central processing unit selects the appropriate set from the memory in response to the actual speed of movement of the object and randomly selects the subsets within the selected set as long as the object remains in a given speed range. In another embodiment, a single set is formed of a plurality of subsets. Each subset contains an identical number of sound representations which vary from subset to subset and within each subset in volume and/or pitch. The CPU randomly selects a sound representation from any of the subsets for each of plurality of consecutively generated sounds. Upon sensing speed variations, the CPU adjusts the length of the leader and/or tail end of each sound for faster or slower sound generation.
U.S. Pat. No. 5,773,939, issued Jun. 30, 1998 to Severson, puts forth command control for model railroading using AC track power signals for encoding pseudo-digital signals for transmitting very fast digital DC signals over the track for remote control in a model railroad layout, by selecting positive and negative lobes from the applied AC track power signal. This method allows digital transmission at 120 Hz rate that can be used within a 60 Hz AC system. This is fast enough to be used for Digital Command Control (DCC) and also capable of delivering large power output efficiently without the expense of filtering or exotic electronic control circuits. This method also has low sensitivity to electrical noise and does not generate significant noise during operation. Methods are described of transmitting and receiving positive and negative lobes and methods to extend this technology, and other areas where this technology can be applied such as remote control of appliances connected to any AC power environment such as home or industrial electric power systems.
U.S. Pat. No. 5,855,004, issued Dec. 29, 1998 to Novosel, concerns a sound recording and reproduction system for model train using integrated digital command control for recording, storing and reproducing sound for playing back in an environment requiring simulated sounds, voices, and/or sound effects. Sounds are recorded on a chip and played back in an asynchronous manner from the chip as a result of activation of a switch or inertial movement within the system. A Hall-effect sensor, reed switch or momentary switch or the like may be implemented for enabling activation of the recorded sound from the chip for broadcasting. A compander compresses the sound on the chip and expands the compressed sound for playback. Employing the above system for audio storage, a sound, motor and special effects controller may be created for model train applications as well. The different functions of the sound unit are controlled through a discrete bi-polar digital command control signal using a unique address for each unit. A synchronous means of play back may also be employed when the system is used with the bi-polar signal using a sensor. In addition to the analog sound storage, the same concepts and ideas may be applied to a digital sound recording and play back device as well.
U.S. Pat. No. 6,014,934, issued Jan. 18, 2000 to Pierson, illustrates a modular circuit board arrangement for use in a model train includes a motherboard mounted on the model train platform. The motherboard has receptacles that accept and communicate signals with a plurality of removable circuit modules for controlling model train operations. These circuit modules may include, for example, a light control circuit module and a sound control circuit module.
U.S. Pat. No. 5,896,017, issued Apr. 20, 1999 to Severson, is for a model train locomotive with a Doppler shifting of sound effects. Electronic circuits and methods are provided for remote control of a locomotive in a model railroad layout having an interruptible DC power supply coupled to the railroad track. The locomotive motor is isolated from the track so as to allow use of polarity reversals on the track power signal for controlling remote effects in the locomotive such as sound and visual effects. An on-board electronic state generator is provided in the locomotive for maintaining one at a time of a predetermined set of states, at least one of the states having a corresponding remote effect associated therewith. Remote control signals such as a pulsed reversal in polarity of the DC track power signal (PRP) or high voltage pulse (HVP) are used to clock the state generator to a desired state, thereby permitting control of a plurality of remote effects using only the traditional DC power supply interface. Further remote effects can be controlled by using the amount of DC voltage superimposed over the AC track signed to indicate, for instance, a desired pitch for the train horn. Alternately, the length in time at which a remote signal is applied to the track can itself serve as coded instructions to an on-board remote control selection memory.
U.S. Pat. No. 4,747,351, issued May 31, 1988 to Baret, provides a solid-state whistle and horn activation system for model railroads. An apparatus is shown for actuating a sounding device for model railroad engines powered by an alternating-current voltage impressed across two rails, which apparatus is completely solid state in nature. The system includes input and output transistors which are normally non-conducting together with means for producing a direct-current bias voltage for turning ON the input transistor when a direct-current bias voltage is superimposed on the alternating-current voltage impressed across the two rails. The input and output transistors are interconnected such that when the input transistor conducts so also does the output transistor to thereby power the sounding device.
What is needed is an inexpensive sound system for model trains.